Inside Microsoft’s two-decade push to cut water intensity while scaling for growth

As demand for cloud and AI services continues to grow, datacenters are becoming more essential than ever. Communities also want to better understand how this infrastructure affects local resources, particularly water. At Microsoft, water stewardship has been a priority since our first datacenter builds in the early 2000s and remains a core part of our strategy today and into the future. It underpins both our Community-First AI Infrastructure initiative and our company-wide commitment to become water positive by 2030, meaning we will replenish more water than we withdraw. We are pairing our progress with continued transparency so people can understand not only how much water we use, but also how we are working to reduce that use over time.

Through continuous innovation and advancements in cooling technologies, we have improved our water use effectiveness (WUE), measured in liters per kilowatt-hour (L/kWh), by nearly 90% since our first generation of datacenters in the early 2000s. Our average WUE has decreased from 2.3 L/kWh to 0.27 L/kWh in 2025, reflecting decades of innovation and our ongoing commitment to reducing the water intensity of our datacenters while meeting the growing demand for cloud and AI services.

Across our entire owned fleet of datacenters, we are committed as a company to a 40 percent improvement in datacenter water-use intensity by 2030. As of 2025, we have reduced our water-use intensity by 25 percent, putting us well over halfway toward our goal. This strong progress reflects the impact of our continued investments in water-efficient cooling technologies, operational improvements and responsible water management practices.*

In FY25, Microsoft reached an important milestone toward its 2030 water positive commitment, replenishing more water than it withdrew across its global operations for the year. We have made this progress by decoupling datacenter growth from water use through resilient, responsible water stewardship practices and the deployment of increasingly efficient cooling technologies — demonstrating that digital growth and sustainable water management can advance together. We are committed to building on this progress and working toward sustaining water positive performance over time as we continue advancing toward our 2030 goal.

Early water stewardship by design

Beginning with some of our earliest datacenter designs, we prioritized water efficiency while minimizing impacts on energy use through the deployment of high-efficiency economizing chillers operating at elevated water temperatures. As early as 2008, we adopted direct air cooling with evaporative assist as the primary cooling approach across our datacenter fleet. This design uses significantly less electricity and up to 90% less water than traditional water-based cooling systems by relying on water only when outside temperatures exceed 85°F (29.4°C). In parts of Northern Europe, no water is required for cooling throughout the year, while in other cooler regions like Dublin and Amsterdam, water is used less than 5% of the time. In more temperate climates like Virginia, water is typically required only 10% of the year, while in the hottest climates like Phoenix, water use may increase to as much as 40% of the year. As a result, approximately 90% of our 2025 owned fleet operates using highly efficient, low- to zero-water cooling systems.

While the majority of our existing datacenters are already highly water efficient, we did not stop there. In 2024, Microsoft introduced a new datacenter design optimized for AI workloads that consumes zero water for cooling during operations, further reinforcing our commitment to water stewardship by design. This chip-level cooling solution delivers precise zonal temperature control without water evaporation by recirculating water through a closed-loop, direct-to-chip cooling system. As our datacenter fleet continues to expand, the addition of these zero-water designs will further reduce Microsoft’s water use intensity over time.

Datacenter cooling methods, explained:

• Cooling towers: Traditional systems that remove heat by evaporating water year-round.
• Hybrid fluid coolers: Evaporates water for cooling during hot summer conditions and switches to dry mode when ambient temperatures cool down.
• Direct air: Uses outside air for cooling, with little to no water use. Water is used only when outside air is above 85°F.
• Air cooled chillers: Uses mechanical refrigeration and outside air to remove heat from closed coolant loops with zero water evaporation.
• Liquid-cooled AI DCs: Uses closed-loop, direct-to-chip cooling to provide precise chip-level temperature control, removing heat efficiently with zero water evaporation.

Modernizing cooling in existing datacenters with smarter controls

Design innovation is only part of the story. We are also improving the efficiency of existing facilities that use water through a continuous focus on optimizing temperature and humidity setpoints, enabling more precise environmental control and eliminating overcooling. In addition, we regularly audit water use and compare actuals against design expectations using real-time weather data and operational analytics. This helps ensure our datacenters are performing as intended and enables us to quickly identify and address any unexpected water use. These efforts, combined with ongoing hardware and operational improvements, are all aimed at using as little water as possible.

Specifically in our Phoenix, Arizona, datacenters, implementation of these advancements led to a 23% year-over-year improvement in WUE in FY25 alone. We are now deploying these advancements across our direct-evaporatively cooled datacenters globally.

Operational improvements like these are one reason Microsoft has been able to report significant long-term reductions in water intensity across datacenter generations. They also point to the next phase of our work: expanding the use of recycled and alternative water sources wherever possible.

Leveraging recycled, reused and non-potable water

In addition to driving efficiency, we also prioritize using recycled, reused or non-potable water wherever possible in our operations. We have expanded the use of these non-potable water sources in some of our most water-intensive regions, helping reduce demand on freshwater supplies. For example, in Quincy, Washington, Singapore and San Antonio, Texas, three of our key locations for advancing water stewardship, we leverage 74%, 99% and 79% recycled, reused or non-potable water sources, respectively.

Rainwater harvesting systems are now operational at select datacenters in the Netherlands, Sweden and Ireland, with additional installations planned in Canada, the United Kingdom, Finland, Italy, South Africa and Austria. To illustrate the potential impact, Microsoft’s new datacenters in Quebec are expected to collect up to 1.5 million liters of rainwater annually, depending on local precipitation levels. This water can be used to further offset the already low water withdrawal at these sites. Expanding the use of alternative water sources in this way helps reduce pressure on municipal water supplies while supporting efficient datacenter operations.

As needed, we implement on-site water treatment systems that enable facilities to recycle water multiple times for cooling operations. These systems produce purified water suitable for reuse within cooling systems, reducing overall dependence on utility water supplies. Together, these efforts demonstrate how engineering innovation and operational excellence can work in concert to meaningfully reduce water use at the facility level.

Advancing water stewardship through investment and community partnership

We work closely with local utilities to reduce strain on community resources, and plan ahead for the sourcing and infrastructure needs associated with our operations. Beyond our operations, Microsoft’s Datacenter Community Pledge commits us to protecting local watersheds, engaging stakeholders and investing in projects that strengthen regional water resilience — helping ensure datacenter growth supports both environmental sustainability and long-term community well-being. Where system improvements are required, Microsoft funds those upgrades in full so communities do not have to shoulder the cost of supporting our operations.

Beyond our own footprint, we invest directly in community water infrastructure by modernizing water systems, expanding access, increasing reliability and helping utilities maintain stable rates and pressure. These investments create shared value for both Microsoft and the local communities we work closely with by strengthening critical infrastructure and supporting long-term water resilience. For example, near our datacenter in Leesburg, Virginia, Microsoft is funding more than $25 million in water and sewer improvements to help ensure that the cost of serving our facilities does not fall on local ratepayers. Since 2020, we have invested more than $500 million in more than 75 water and wastewater infrastructure projects that deliver meaningful community co-benefits.

Replenishment

Finally, we pair all of this work with our broader water positive commitment, our goal to replenish more water than we withdraw by 2030, while advancing our Community-First AI Infrastructure approach, which prioritizes delivering measurable benefits to the communities where we operate. This approach extends across our entire datacenter footprint, including leased facilities. In FY25, we replenished more water than we withdrew globally, marking a significant milestone in our water stewardship journey.**

We prioritize and pursue projects designed to deliver meaningful water contribution to each local community. For example, in the greater Phoenix area and nearby Nevada communities, we partner with FIDO Tech and local utilities to deploy AI-enabled leak-detection that identifies and repairs hidden breaks in aging water systems. By preventing water loss before it occurs, these efforts help keep more water in circulation, improving reliability for residents and effectively increasing the amount of usable water available across the system.

Across the Midwest, we work with The Nature Conservancy to restore historic oxbow wetlands — crescent-shaped water bodies that naturally recharge groundwater, reduce flood risk and enhance habitat for native species. These wetlands act as natural reservoirs, capturing and slowly returning water to local aquifers over time. The goal is to create more stable water availability for agriculture, healthier ecosystems and increased resilience for nearby communities throughout the year.

Looking ahead

As water challenges become increasingly complex around the world, Microsoft remains deeply committed to protecting water as a vital natural resource. We continue to advance datacenter innovations that reduce water use intensity while supporting the growing performance demands of cloud and AI services. Through zero-water cooling designs optimized for AI workloads, water reuse initiatives both on and off our campuses and community-focused stewardship programs, we are working toward a future where digital growth and responsible water management go hand in hand.

We are also exploring zonal cooling architectures that more precisely align cooling approaches with the needs of different hardware types, improving efficiency while supporting a diverse mix of AI and traditional workloads.

Datacenters are essential infrastructure for the digital economy, and we believe they should be built and operated in ways that benefit the communities they serve. Over the last decade, we have demonstrated that technological advancement and environmental stewardship can progress together, and we remain committed to continuing that journey as we build the datacenters of the future.

Top image caption: Aerial view of Microsoft datacenter campus in Wisconsin.

Judy Priest leads technology strategy, innovation and research for Microsoft’s global cloud and AI infrastructure, driving advances in datacenter architecture, sustainability, power, cooling, energy and emerging technologies that enable reliable, scalable services.

Steve Solomon is a professional engineer leading the engineering strategy behind the company’s global cloud and AI infrastructure. He specializes in datacenter design, sustainability, power and cooling innovation, helping advance reliable, efficient and community-focused infrastructure at hyperscale.

*Footnote 1: Measured as water withdrawals per megawatt (MW); based on a 2022 baseline.

**Footnote 2: To understand how Microsoft calculates and tracks water replenishment data, please refer to our FY 2024 Environmental Data Fact Sheet.

Tags: datacenters